User blog:Fuse809/Bacterial infections I consider the most interesting.
A short while ago I thought I might do a status on my favourite'In terms of the degree of interest it sparks in me, not in terms of its impact on real people 'bacterial infection but I realized that I could not really narrow it down to just one so instead I am going to list my five favourite bacterial infections, in no particular order. Anthrax The first one is anthrax because even though it is not transmissible person to person '''it '''inspires the greatest degree of fear in us and for good reason too. It is because unlike most bacterial infections where antibiotics and other forms of medical care have basically conquered them for us, anthrax in its inhalational formWhich is caused by one inhaling the spores is almost always fatal, even with aggressive therapy. Additionally anthrax spores (which are dormant forms of the bacteria, sort of like time capsules they protect the bacteria for decades from the environment only to resurface again sometime in the future) can survive in the environment (outside a living host, like humans) for over 50 years and can withstand most disinfectants. Mycobacterial infections The second one is, well it is a pair of bacterial infections that are caused by a number of closely-related bacterial organisms: leprosy'Usually caused by ''mycobacterium leprae (M. leprae) and '''tuberculosis.Usually caused by M. tuberculosis, but some cases are due to M. bovis (which is called bovine tuberculosis) Collectively they are called mycobacterial infections and what interests me about them is how ancient they are; leprosy appears extensively in the historical records of ancient civilizations, for example many of us have heard of leprosy in Bible school. Evidence of tuberculosis appears in the skeletal remains of the Ancient Egyptians (dating back to 1000 BC) and Neolithic European civilizations (dating back to 8000 BC), as tuberculosis can affect the bone in rare cases causing a disease called Pott disease. Mycobacterial organisms are all primarily intracellular microbes, which means they generally prefer to live inside the cells of their hosts (e.g., in humans M. tuberculosis and bovis often takes up residency within the macrophages type of immune cell found within virtually all our tissues found in our lungs or digestive tract) as opposed to extracellular microbes which prefer to live outside said cells. They are also known to cause characteristic immunologic phenomenon, which is a fancy way of saying the way the immune system reacts to them often causes characteristic reactions in those affected, some of which are potentially harmful to the host (i.e., the person affected). Leprosy For example, leprosy is known to cause erythema nodosum leprosum, (ENL) a rare inflammatory skin reaction caused by the body's immune response against the microbe, as opposed to the direct effects of the bacterial organism. By the way, ENL was the first disease that thalidomide was approved to treat in the U.S., in 1998, as it was discovered that in ENL thalidomide produces rapid and robustSuperior to all other known treatments, by-the-way improvements in moderate-severe ENL. In ENL it seems like thalidomide works by inhibiting the secretion of tumour necrosis factor alpha (TNF-α) a pro-inflammatory protein secreted by the immune system. Despite its clinical effectiveness, because of its risk of causing birth defects (including a 40% mortality rate in infants born to mothers who took the drug whilst pregnant) the World Health Organization (WHO)﻿ has consistently recommended against its use in ENL. Overall leprosy causes two major manifestations: the less severe tuberculoid and the more severe lepromatous leprosy. Both subtypes shown different immunologic response profiles at sites of disease: tuberculoid leprosy (TL) is characterized by a more powerful TH1 immune response whereas lepromatous leprosy (LL) is characterized by a greater TH2 immunologic response. I should mention, however, that patients with leprosy fall on a continuous spectrum between tuberculoid and lepromatous subtype. Interestingly most people are naturally immune to leprosy nowadays, which is likely testament to how long our species has battled against the microbe in the past as this battle could leave marks in the form of favouring genes that convey immunity to the microbe. There exists a vaccine that provides some protection from tuberculosis and leprosy (the BCG vaccine) but the protection from it is limited and even after the vaccine some people still get these diseases after exposure, despite a healthy immune system. The BCG vaccine, btw, is also administered into the bladder of patients with bladder cancer where it is in fact a very effective treatment against the cancer. This likely reflects how immunogenic (i.e., how efficiently mycobacterial organisms elicit an immune response) these organisms are as a consequence of BCG vaccination in bladder cancer is the cancer cells get caught in the immune system's cross-fire. Notes Reference list